Door lock



H. H. Kl'sTNER Dec. 7, 1937.

DOOR LOCK Filed Jan. 29, 1936 gmc/rdm Patented Dec. 7, 1937 UNITED STATES DOOR LOCK Herman H. Kistner, Baltimore,v Md., assignor to Kistner Lock & Appliance Company, a corporation of Maryland Application January 29, 1936, Serial No. 61,382

5 Claims.

This invention relates to mortise locks and rim locks employing locks of the pin tumbler type usually called cylinder locks, and its object is to make them secure against forcible opening. In this type of lock the bolt action is actuated by an arm on a rotating plug mounted in the cylinder lock which is received in a hole bored for it in the door and is screwed into the door lock casing from the outside and held therein by a set screw or similar detent.

A serious defect of this type of lock is that the cylinder can be forcibly unscrewed from the outside by means of a Stillson wrench applied to its exterior flange, or heavy screw driver' applied to the key slot.

Another defect of locks of this general type, is that the pins that normally prevent the plugs from turning can be cut in two by drilling in from the outside on the line of intersection between the exterior of the plug and the vertical axial plane oi the cylinder and pins, and the plug freed so that it may be turned with a screw driver inserted in the screw slot.

These defects it is the object of the present invention to overcome in a simple and effective manner, and at no great increase in cost of the lock.

An illustrative embodiment of the invention is shown in the accompanying drawing, wherein Fig. 1 is an outside view of a portion of a door at the lock, showing the door broken away to disclose the lock casing;

Figs. 2 and 3 are respectively a vertical crosssection thereof on the line 2-2 and a horizontal section on the line 3 3 in Fig. 1;

Fig. 4 is a cross-section on the line 4-4 in Fig. 2, looking in the direction of the arrows, showing a portion of the inside of the lock casing; and

Fig. 5 is a cross-sectional view to a larger scale ol a portion of the rim of the lock cylinder.

The lock illustrated in the drawing has a casing II, secured in a mortise in the door I by means of screws I2 passing through the face flange I3, in the usual manner. The cylinders I4, I5, which carry the key actuated plug I6 and thumb latch I 'I for operating the lock mechanism, screw into the flanged openings I8 in the casing and are secured there by means of a keeper, such as the yoke I9, the bifurcated ends of which engage in one or the other of the grooves 2B. The yoke is slidable axially to clamp the cylinders and is held in clamping position by means of a screw 2|, which passes through the face ange I3 and is inaccessible when the door is shut.

The sliding bolt 25 and its lockingmechanism 2B are actuated by arms 2l on the inner ends of the plug I6 and thumb latch Il, respectively, as. is common in locks of this type.

The outer cylinder I4, which carries the key n operated plug I6, is fitted with a loose flange 30 made of case hardened steel or hard bronze, secured in place by an expanding ring SI arranged in alining grooves in the flange and cylinder respectively, the groove in the cylinder being deep enough to receive the full thickness of the ring in compressed position so as topermit the flange to be slipped over it into place, asshown in Fig. 5. When the ring expands into the groove in the flange, the latter is locked on the cylinder and cannot be removed without breaking it. Between the flange and the door is the usual loose ferrule 32, to i-lll the gap between the ilange and face of the door on doors of less than maximum thickness.

The first two locking pins 33 and their drivers 34 are made of hardened steel to prevent drilling through them, the construction of the remaining locking pins 35 and drivers 36, and the tumbler springs 3l being the same as usual in this type of lock. l

On the inner end of the outer cylinder I4, between it and the adjacent arm 21 carried by the plug I6, is secured an adjustable retaining sector or guard 4B, which projects beyond the periphery of the cylinder and engages behind the flange 4I on the lock casing Surrounding the threaded opening for the cylinder, so as to prevent unscrewing the latter, as shown in Fig. 4. This sector is held in place by two countersunk screws 42, 43, and is provided with a short slot 44 instead of a circular hole for the screw 43 to enable it to be swung inwards a little when the screws are loosened to permit the cylinder to be screwed in and out of the casing. These screws 42, 43, are readily reached with a screw driver from the inside side of the door through the opening for the thumb latch cylinder I to tighten and loosen them and manipulate the sector when the outer cylinder I4 needs to be changed.

The loose flange 30 and guard sector 40 prevent forcible unscrewing of the cylinder I4 by a Stillson wrench, cold chisel or other implement readily applied to the outer end of the cylinder or inserted in the key slot, and neither the ange nor the guard can be removed by any force that can be applied while the cylinder is in the casing.

I have described what I consider to be the preferred form of my invention, but the invention is not restricted to the construction shown in the drawing.

What I claim is as follows:

1. In a door lock having means engaging the periphery of a cylinder lock for retaining the cylinder from being unscrewed from the lock casing when the door is closed, the combination of a cylinder lock, guard means fixed on the inner end of the cylinder for engaging the door lock inner face of the casing to prevent forcible unscrewing of the cylinder.

2. A cylinder for a pin tumbler lock adapted to screw into a door lock casing, said cylinder having a plug with an operating arm at its inner end, and guard means arranged between said operating arm in its normal position and the adjacent end of said cylinder and adapted to be xedly secured thereto with a portion projecting radially beyond the periphery of the cylinder to engage the inner face of the lock casing and prevent unscrewing of said cylinder when assembled therewith.

r3. A cylinder for a prin tumbler lock having a sector shaped guard plate with a screw receiving slot secured on its inner end by means permitting outward adjustment thereof when in place, said means comprising two xed screws one of which passes through the slot in the guard plate.

4:.I In a door lock having means for engaging the periphery of a cylinder lock for retaining the cylinder from being unscrewed from the lock casing when the door is closed, the combination of a cylinder lock, a pivoted guard means carried by the cylinder adjacent to its inner end for engaging the inner face of the door lock casing to prevent forcible unscrewing of the cylinder, and means for xedly securing said guard means in adjusted position to the end face of the cylinder, said means being adjusted from within after the cylinder is installed in the lock casing, whereby it cannot be removed except from within.

5. A cylinder casing for a pin tumbler lock having a groove on its outer surface adapted to be engaged by a keeper for retaining it in 4a door lock casing, and a sector shaped guard carried 'by said cylinder casing adjacent its inner end between it and the path of movement of the bolt actuating cam and projectable into the door lock casing to engage the inner Wall thereof for pref venting forcible removal of the cylinder therefrom,y said guard having securing means adjustable, to hold it out of operative position during the operation of assembling the lock and in operative position after the cylinder is installed in the door lock casing, said means being adjusta-ble' from within only when assembled in the door lock casing.

' HERMAN H. KISTNER. 

